摘 要：In Japan, the Joint
Special Design Team for Fusion DEMO contributes todevelop JA DEMO as
the national team. Recently, plasma theory andsimulation working
group has drawn up an intermediate term research planto contribute the conceptual design of JA
DEMO. In this presentation, wewill briefly
introduce the activity of plasma theory and simulationresearch for DEMO.

convective cell
modes) and resistive ballooning mode turbulence after the pedestal collapse is
numerically studied by a four-field reduced MHD model in the BOUT++ framework. The
strong flow shear sup- presses the radial transport of pressure filaments, and
the pressure profile in the pedestal region is partially recovered. As a
result, a secondary instability is quasi-linearly excited, which yields a
secondary collapse. The subsequent damped oscillation is also analyzed by phase
diagram analysis.

题
目： Characteristics
of ITG turbulence and associated global profile

formation in
flux-driven gyrokinetic simulation （ Dr. WANG Wei）

摘 要：Global nature of
multi-scale turbulence is of specifically importance in

understanding and
evaluating transport levels in Tokamak plasmas. Based on flux-driven
gyrokinetic simulations using GKNET, characteristics of ITG turbulence and
associated global profile formation are discussed through several approaches
including Fourier-based analyses and the newly developed size-PDF analysis

题目：First application of the self-consistently coupled full-wave/Fokker-Planck analysis for the modeling of the LHW experiment on EAST

报告人：杨程

主持人：陈佳乐

时间：2020年1月3日（星期五） 15:30—16:30

地点：506办公室

摘要：

Lower hybrid wave
is the most important auxiliary heating and current drive tool on EAST. Both ray-tracing and full wave codes have
been used to model the LHW physics for the EAST experiments. Recently the
self-consistently coupled full-wave/Fokker-Planck analysis has been successfully
carried out for this domain. The process of the iteration between the full wave
code(TORLH) and the Fokker-Planck code(CQL3D) will be introduced. The results
including the spectrums with poloidal broadening, the wave electric fields, the
power density profiles and the electron distribution function will be
presented..

Resonant
magnetic perturbations (RMP) have extensively been demonstrated as a plausible
technique for mitigating or suppressing large edge localized modes (ELMs). The
plasma response to RMP plays a key role in the suppression of ELM with RMPs. A
linear model of plasma response is developed in BOUT++ framework. The
penetration process of the resonant component of the radial magnetic field is
achieved from the simulation. Also its dependence on resistivity and plasma
rotation is also obtained.

Linear stability and nonlinear dynamics of the fishbone instabilities with reversed safety factor profile have been investigated by the global kinetic-magnetohydrodynamic (MHD) code M3D-K. For the consideration of the fishbone instability, there are two different types of the fishbone instability: dual resonant fishbone (DRF) with double q = 1 surfaces and non-resonant fishbone (NRF) with the minimum value of safety factor qmin a little larger than unity. Based on EAST-like parameters, linear simulations show that the DRF is excited by the trapped beam ions when the fast ion pressure increases to exceed a critical value, and the mode structure of DRF exhibits splitting feature due to double q = 1 surfaces. When qmin increases from below unity to above unity, the fishbone instability transits from the DRF to the NRF, and the mode frequency of the NRF is higher than the DRF as the NRF is resonant with fast ions with larger precessional frequency. Nonlinear simulations show that the saturation of the DRF is due to MHD nonlinearity with a large n = 0 component. However, the saturation of the NRF is mainly due to the nonlinearity of fast ions, and the frequency of the NRF chirps down nonlinearly. The fast ions are redistributed and become flattened due to the DRF or the NRF, and the transport level of the fast ions due to the NRF is weaker with more centrally radial redistribution region in comparison with the DRF.

Radiofrequency
wave in ion cyclotron range of frequency (ICRF) is an important way for heating
plasma, driving current and implementing plasma control in the magnetic fusion
devices such as EAST and ITER tokamak. Achieving good coupling of ICRF power
into the plasma is an essential issue for high power ICRF injection on EAST
tokamak. In this talk, we present the Modeling of ICRF power injected into 3D
EAST plasmas via the high performance Finite-difference time-domain (FDTD)
model in VSim software. Realistic 3D ICRF antenna module and box of the B-port
on EAST have been constructed as geometry in the simulations. The effects of
antenna structure, antenna phase, minority ion, distance between antenna and
plasma, and toroidal curvature on the ICRF coupling and propagation are
discussed.

题目：Recent progress in the development of gyrokinetic semi-Lagrangian code NLT

报告人：叶磊

主持人：甘春芸

时间：2019年12月6日（星期五） 15:00—16:30

地点：4楼中间会议室

摘要：

Large-scale gyrokinetic simulation has become an indispensable tool to study low frequency phenomena in tokamak plasmas, including turbulence transport, zonal flows and energetic particle physics. NLT is a 5D continuum gyrokinetic code based on the I-transform theory model. In this talk, a brief introduction to the basic gyrokinetic theory and simulation models will be given. Recent progresses in the code development, including multi-ion species, kinetic electrons and the hybrid spectral semi-Lagrangian method will be reported.

题目：Impurity Convective Particle Transport Driven by the Impurity Rotation in the Tokamak Plasmas

报告人：潘成康

主持人：叶磊

时间：2019年11月29 （星期五） 15:30—16:30

地点：4楼会议室

摘要：

The
neoclassical impurity convective particle transport in the rotating tokamak
plasmas has been investigated analytically. The Coriolis force effect duo to
the combined effect the impurity toroidal and poloidal rotation on the poloidal
asymmetry of the impurity density is included in the impurity neoclassical transport
theory. The radial impurity particle transport purely driven by the impurity
toroidal and poloidal rotation is identified explicitly. The new screening
effects on the impurity radial transport due to the impurity co-current
toroidal rotation and the impurity poloidal rotation in the ion-diamagnetic
drift direction are discovered

The
investigations on the interaction between electromagnetic (EM) waves and plasma
are important in theoretical, experimental and numerical research of fusion
plasma. Low hybrid wave (LHW) injection is one of the effective methods to heat
the plasma to achieve fusion reaction. Due to the steep density gradient and
large fluctuations in tokamak edge region, the more accurate results can be
obtained by using the numerical method than the theoretical WKB method.
Especially in low frequency range, when the density profile has the large local
gradient caused by fluctuation or the gradient scale length is comparable with
the wavelength of incident EM waves. In this work, a nonuniform plasma model is
used, and the different density gradient profiles with fluctuations are applied
to investigate the impact of density profile on LHW propagation in tokamak edge
plasma using 1D finite difference time domain (FDTD) simulations. From
simulation, the temporary evolution and spatial profiles of plasma variables
and EM waves such as the density, velocity, current, electric field, magnetic
field, Poynting vector, EM wave power, etc. are obtained. The full-width at
half-maximum (FWHM) of radial EM wave power profile is affected by the
different incident EM wave frequency, the collision frequency, the plasma
density, together with the amplitude and the wave number of fluctuations. Those
results will help to understand the LHW propagation in edge plasma.